89.1k views
15 votes
F(x) =3x+8 find the inverse of f(x)

User Ewan
by
6.6k points

1 Answer

9 votes

Answer:

Explanation:

Hi!

To find the inverse, first we express your function as:

y = 3x - 8

Then, we interchange x and y variables:

x = 3y - 8

From there, we isolate y:

x + 8 = 3y

x/3 + 8/3 = y

Then, the inverse, g(x) = (x+8)/3.

We can check this by getting g(f(x)):

(f(x) + 8)/3 = (3x - 8 + 8)/3 = 3x /3 = x.

This is correct by the definition of the inverse function.

You can also think about the inverse as a "reverse function", so for example, in f(x) = 3x-8, x is multiplied by 3, then 8 is subtracted from it.

If we are to go from f(x) to x, we first add 8 (to reverse the subtraction), then divide by 3 (to reverse the multiplication).

This means g(y) = (y+8)/3, the same answer.

Hope this helps!

User Octavio
by
7.2k points